Process and apparatus for artificially reconstituting daylight



Dec. 1924. C. H. A. GAMAIN PROCESS AND APPARATUS FOR ARTIFICT'ALLY' RECONSTITUTING DAYLIGHT Fild 'Sebf 17. 1923 Patented Dec 16, i924a PATENT OFFICE.

. CHARLES HENRI ALFRED GAMAIN, OF PARIS, FRANCE.

PROCESS AND APPARATUS FOR ARTIFICIALLY RECONSTITUTING DAYLIGHT.

Application filed September 17, 1923. Serial 663,232.

To all whom it may concern:

Be it known that I, CHARLES HENRI AL- FRED GAMArN, citizen of the Republic of France, residing at Paris, France (post-oflice address 82 Rue Compans), have invented certain new and useful Improvements in Processes and' Apparatus for Artificially Reconstituting Daylight, of which the following is a specification.

1c The present invention relates to the production of artificial daylight; and its object, stated briefly, is toprovide an 1mproved lamp or equivalent lightlng apparatus or device which is constructed in such away as to overcome the defects inherent in apparatus of the character indicated now in use.

These defects, as is generally known, primarily involve distortion of colors an strains upon the eyes, and they are chiefly due to differences in the spectral composition of natural and artificial light, the latter being characterized by the presence of the red and yellow rays in increased quantity and by a decrease in the blue-green and violet rays. It has been proposed to correct these defects in various ways; but, so far as I am aware, such attempts have heretofore been unsuccessful.

According to my invention, however, an artificial light is produced which has, to all intents, the same, or substantially the same, spectral composition as daylight; th1s result being obtained by means of the apparatus hereinafter described. The lmproved apparatus which, therefore, constitutes the subject matter of the invent on, comprises an electric lamp bulb of blue-tinted glass filled with argon or other gas of like character and operating under a higher voltage than that for which the lamp is designed; such bulb having associated with it a special arrangement of reflecting mirrors and, in combination therewith, a filter and a screen.-

The effect of the high voltage of the current passing through the lamp filament is to heat the latter to a greater degree of incandescence than occurs in the standard halfwatt lamps, so that the lamp is thereby caused to emit an increased quantity of blue rays, in order to bring the spectrum of its light nearer to the spectrum of natural daylight. The blue tinting of the glass, on the other hand, has the effect of intercepting the orange-yellow rays which are still emitted in great number in spite of the increased incandescence of the filament.

As to the reflecting mirrors, these are s lvered and are arranged in one or more an only to obtain the maximum efficiency by refleeting, with the least possible amount of absorption, all the rays which have not been intercepted by the colored glass of the bulb, but also to obtain a much whiter artificial light than has heretofore been obtained. This light still differs, however, from natural daylight in that the latter has a tendency toward the violet; and it is to correct that fault that the filter and screen mentioned above are utilized, the filter comprising a very thin glass plate interposed in the path of the light which is tinted or colored Violet throughout, said plate intercepting only a very small portion of the useful rays, without the interposition of opal or blue-tinted glass. If necessary, it can be faced with a plate of lead glass in order to intercept the greatest portion of the ultra-violet rays.

which may be present in the light emitted by the overcharged filament; the light finally obtained by the combination of the above-mentioned features being identical with natural light in so far as concerns its spectral composition (visible rays) and producing neither color-distortion nor eyestrain.

In the accompanying drawings, two embodiments of an illuminating apparatus or lamp oonstructed'in accordance with the invention are shown.

' Figure 1 of said drawings is an elevation of the improved apparatus. 6

Figs. 2 and 3 are, respectively, a vertical section and a plan view of a reflector comprising a single row of mirrors, the lamp bulb also being illustrated in Fig. 2.

Figs. 4: and 5 are, respectively, an elevation and a plan view of a multi-row reflector.

Referring more particularly to the drawings, 1 (Fig. 2) indicates the blue-tinted bulb of the lamp proper, the filament of which is designed to be traversed by a current of higher voltage than that for which it was originally constructed. The voltage may, for example, be about 5to 10% higher jected to a current of 110, volts, or one.con-' than the normal one, so that a lamp' intended for a current of 105 -volts may be suband 5).

In either case, the reflecting mirrors in-- clude certain ones which are of uncolored glass indicated at 2, and others which are const ructed either of blue-tinted glass (indicated at 3) or of violet glass (designated 4) all of the mirrors being silvered and coated with a substance which ermits them to resist the high heat radiate by the bulb. The mirrors are disposed at an angle to the vertical which varies according to the result sought. In the construction shown in Figs. 2 and 3, the angle in question isapproximately 37. 30'; but while good results have been obtained therewith, that particular angle is mentioned merely by way of example. For apparatus of high power (.400 to 3000 G. P.), it is preferable to adopt a construction such as that represented in Figs. 4 and 5, in which the reflector comprises three concentric rows of mirrors arranged, respec tively, at angles of 27, 40 and 66 30' to the vertical; these angles likewise being given merely as examples. Speaking generally'the arrangement of the-mirrors and the angles at which they are disposed will depend largely upon whether a concentrating ora dispersing action upon the'rays 1s required and the extent of such action, for

- it will be apparent that the converging rays reflected by the mirrors may either be concentrated on a point at a desired distance, or ma be distributed over a surface the sizeiofl which depends upon the power of the apparatus and upon its height above the surface to be illuminated.

The filter interposed in the path of the reflected rays is indicated at 5 (Fig. 2) and, as previously stated, consists of a thin plate of violet-colored glass, beneath which there is disposed the lead glass screen 6; the respective functions of said parts being to increase the contentof violet rays in the light passing through the filter (i. e., to increase the. tendency of that light toward the violet and thus bring its spectral composition still closer to that of daylight) and to intercept the ultra-violet rays. I

The above assemblage (that is to say, the bulb, its reflector and the associated filter and screen) is mounted within a casing or frame 7 which may have the form illustrated in Fig. 1, for example, or any other desired form, and which may be provided with efiects of the abnormal voltage upon the life of the bulb.

The invention, as above described, may

be utilized for any purpose where a light identical with daylight is-necessary or desirable; for instance, for illuminating drawing tables, operating tables, etc. It is .par-

ticularly useful for surgical purposes, and

especially for surgery of the eye; and when 1 used in that connection, as well as in others,

it may be combined with any suitable optical system.

I claim as my invention 1. An illuminating apparatus for producing artificial daylight, comprising an electric light bulb colored blue throughout and containing an incandescent filament designed to'be traversed by a current of higher voltage than that for which it was constructed; and a reflector encircling said bulb and embodying a row of silvered glass mirrors dlsposed at an incline to the vertical, certain of said mirrors being colorless and others being colored in shades, of blue and violet.

2. An illuminating apparatus for producing artificial daylight, comprising a colored electric bulb containing an incandescent filament designed to be traversed by a current of higher voltage than that for which it was constructed; and a reflector encircling said bulb and embodying a row of silvered glass mirrors inclined to the vertical, certain of the mirrors being colorless and others colored.

3. An' illuminating apparatus for produc-' ing artificial daylight, comprising an electric light bulb colored blue throughout and containin an incandescent filament designed to he, voltage than that for which it was constructed; a reflector encircling the bulb and embodying a row of silvered glass mirrors inclined to the vertical, certain of the mirrors being colorless and others being colored in shades of blue and violet; and a violet filter interposed in the path of the light reflected by said mirrors. 4

4. An illuminating apparatus for producing artificial daylight, comprising 'an electric light bulb colored blue throughout and containing an incandescent filament designed traversed by a current of higher to be traversed by a current of higher voltage than that for: which it was constructed; a reflector encircling the bulb and embodying. a row of silvered glass mirrors inclined glass mirrorsinclined' to the vertical, oer-- colored: and a violet man ate posed in the path of the light reflected by said mirrors and having a screen of lead glass disposed beneath its under face.

5. An illuminating apparatus for producing artificial daylight, comprising a colored electric light bulb containing an incandescent filament designed to be traversed by a current of higher voltage than that for which it was constructed; a reflector encircling the bulb and embodying a row of silvered tain of the mirrors being colorless and others ti ter interposed in the path of the light reflected by said mirrors.

ing artificial daylight, comprising a colored electric light bulb containing an incandescent filament designed to be traversed by a current of higher voltage that that for which it was constructed; a reflector encircling the bulb and embed ing a row of silver-ed glass mirrors incline to the vertical, certain of the mirrors being colorless and others colored; and a violet filter interposed path of the light-reflectedby saidmirrors and having a screen of lead glass disposed beneath its under face.

lln testimony whereof ll atlix my signatnre. 6. An illuminating apparatus for produc- QIHAREES HENRl AMFREEB GAMMN.

in the 

